Well, paint me red and call me a girl scout, I totally did not see this one coming at all. This is so utterly surprising it made my brain explode. Hold on to your panties, because this will rock your world. After pressuring several smaller Android vendors into submission (and yes, HTC is still relatively small compared to other players), Microsoft is now moving on to the big one: Redmond is demanding $15 for every Samsung Android device sold. Samsung's choices are simple: pay up, or face another epic lawsuit.

Apple and Microsoft have broad based cross-licensing agreement in place. Google, supposedly, can't be sued because they are giving their stuff away for free. The bigger question is, why is Google not indenmifying its hardware partners against threats of suits wrt the software that Google provides them, like Microsoft does for its partners? (Maybe because Google knows that they are infringing on patents left and right, and don't want to pay the bill themselves.) Whatever the reason, Google's business model is to pass along the licensing responsibilities and related risks to their partners.

IMO Molly Microsoft have not sued Google because Google's Android product is just software. Software itself is mathematics, it is not patentable subject matter (even in the US) under the "machine or transformation" test.

In United States patent law, the machine-or-transformation test is a test of patent eligibility under which a claim to a process qualifies to be considered for patenting if it (1) is implemented with a particular machine, that is, one specifically devised and adapted to carry out the process in a way that is not concededly conventional and is not trivial; or else (2) transforms an article from one thing or state to another.

The form in which Google makes Android available to OEM's is not a form which is implemented in a specific machine.

So Microsoft can only try out their extortion tactics against people who sell actual devices, such as TomTom, B&N, HTC or Samsung.

In B&N and perhaps Samsung, Microsoft may have bitten off more than they can chew. These firms may decide to fight back. After all, if Microsoft are asking $15 per device for a few very dubious patent claims, and yet they charge about the same to OEMs for the entire WP7 OS, then if nothing else at least B&N and Samsung already have a slam dunk case that Microsoft are not being fair and reasonable.

IMO the same "machine or transformation" requirement under US law is the reason why Microsoft have not tried to directly extort Linux developers, or Red Hat or Ubuntu.